Means for cooling and heating a seat structure

ABSTRACT

A seat structure such as a vehicle seat or a portable pad capable of being placed upon a seat structure including a heat pipe assembly having an elevated portion responsive to body heat of an occupant in the area where the body engages the seat or pad thereby heating and cycling a volatile fluid in the heat pipe to the elevated portion which is in thermal communication with the ambient environment for continuously cooling the seat or pad area engaged by the occupant. A selectively energized heater can be disposed within or near the volatile fluid for activating the heat pipe cycle and continuously warming the body engaged surfaces of the seat or pad as desired. The heat pipe can be formed as an integral part of the pad or the seat structure by incorporating a sealed impermeable plastic passage containing the appropriate volatile fluid.

United States Patent 1 Jacobs June 12, 1973 [75] Inventor: James W.Jacobs, Dayton, Ohio [73] Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: Mar. 15, 1972 [21] Appl. No.2 234,908

[52] US. Cl. 297/180, 165/45, 165/105,

5/284, 219/217, 296/63, 126/205, 128/377 [51] Int. Cl. A47c 7/74 [58]Field of Search 165/105, 45;

2,011,004 9/1970 Germany 297/180 Primary Eagqminer-Albert W. Davis, Jr.A ttorney- Frank J. Soucek and Charles R. Engle [57] ABSTRACT A seatstructure such as a vehicle seat or a portable pad capable of beingplaced upon a seat structure including a heat pipe assembly having anelevated portion responsive to body heat of an occupant in the areawhere the body engages the seat or pad thereby heating and cycling avolatile fluid in the heat pipe to the elevated portion which is inthermal communication with the ambient environment for continuouslycooling the seat or pad area engaged by the occupant. A selectivelyenergized heater can be disposed within or near the volatile fluid foractivating the heat pipe cycle and continuously warming the body engagedsurfaces of the seat or pad as desired. The heat pipe can be formed asan integral part of the pad or the seat structure by incorporating asealed impermeable plastic passage containing the appropriate volatilefluid.

3 Claims, 8 Drawing Figures PATENTED JUN I 2 973 SIEEIINZ PATENIEB l2973 SHEHZNZ r N H MEANS FOR COOLING AND HEATING A SEAT STRUCTURE Thisinvention relates to a seat structure incorporating a heat exchange orheat pipe assembly for warming or cooling an occupant as prevailingconditions require. More specifically, this invention relates to such aseat structure wherein the heat pipe is responsive to body heat of anoccupant to effect cooling of the occupant and further can include aselectively energized heater for warming the occupant.

Providing adequate cooling or warming of a seat occupant as climateconditions dictate has been the objective of many systems in the past.These systems necessarily involve complex plumbing and controlarrangements usually requiring the system to be fixed in place. Thisinvention provides a means for both heating and cooling a seat structurewherein the means can be portable or it can be incorporated in a seatstructure without necessitating significant installation requirements.Since the means accomplishing the heating and cooling is a heat exchangeor heat pipe assembly it is only nec essary that the heat pipe bedisposed adjacent surfaces engaged by a body occupying the seat and thatthe closed container of the heat pipe include a condenser end elevatedrelative to a heat sensing boiler end. Heat generated by a bodyoccupying the seat structure creates a temperature differential betweenthe boiler end and the condenser end of the heat pipe assembly, the heatbeing effective to vaporize a volatile fluid in the heat pipe at theboiler end causing the vapors to rise to the condenser end and condenseto a liquid which flows back to the boiler through either capillaryaction, by gravity or by a combination of both. The condensing of thevapors at the condenser end results in a discharge of heat in an area ofthe seat not engaged by the occupant by virtue of the seat portioncontaining the condenser being in thermal communication with the ambientenvironment. The removal of heat at the condenser provides a coolingeffect at the boiler end where the occupant engages the seat.

Means for providing warming of the occupant can readily be incorporatedin this arrangement by merely providing, for example, a cartridge typeelectric heater within or in the vicinity of the boiler end of theintegral heat pipe assembly. The electrical heater can be connected incircuit with the vehicle power source such that the operator canregulate the supply of current to the heater vaporizing the volatilefluid and initiating the continuous vaporizing-condensing cycle in theheat pipe assembly warming the occupant. If it is desired that the seatshould only include means for cooling the occupant or if it is providedwith a plug-in electrical connection the assembly obviously can ineither situation be entirely portable.

The heat pipe assembly can be a separate sealed container filled with avolatile fluid such as trichloromonofluorornethane, commonly referred toas R1 1 Freon. Of course, any volatile fluid that is readily capable ofbeing vaporized in response to a slight temperature differential betweenthe boiler end and the condenser end of the heat pipe would also bereadily effective. In the situation where the seat is of the typeincluding a nonpermeable plastic cover material over a plasticcushioning foam such as open-cell polyurethane, then passages adjacentthe portions engaged by an occupant could be heat or otherwise sealed inthe cover material retaining the volatile fluid in the areas so engaged.An-

other method of obtaining the same result is by providing passages inthe cushioning foam so that fluid flow is adjacent surfaces engaged bythe occupant. Since it is common practice to provide a slight elevationfrom one edge of a seat portion toward another portion either in a seatbottom or back, such elevation is sufficient to render the integral heatpipe assembly operative in response to heat supplied either by the bodyengaging the boiler end or by energization of the aforementionedelectric cartridge type heater.

It is, therefore, a general object of the present invention to provide aheat exchange or heat pipe assembly in association with a seat pad orseat structure effective to cool portions of the seat engaged by anoccupant.

A more particular object of the present invention is to provide a heatpipe assembly in a seat pad or seat structure integral with the pad orstructure by sealing passages in a plastic cover material in areas ofthe seat engaged by an occupant, the assembly not requiring utilizationof additional components.

A further object of this invention is the provision of a heat pipeassembly formed by sealing impermeable plastic seat covering materialsinto a closed container filled with a porous plastic cushioning foamwherein the container is filled with a volatile fluid and is responsiveto heat generated by the body of an occupant so that the fluid isvaporized and rises through the foam to an elevated end where itdischarges heat and condenses to a liquid and returns through the foamto the heat receiving end thereby continuously cooling the portions ofan occupant engaging the seat structure.

Another object of the present invention is to provide a heat exchange ora heat pipe assembly in a seat pad or seat structure wherein the heatpipe comprises an elongated closed container having a lower boiler endand an upper condenser end, the lower boiler end having an electricheater disposed adjacent thereto or therein for heating the volatilefluid in said container to a temperature above body heat and vaporizingit so that the vapors rise toward the condenser end condensing into aliquid discharging heat, the liquid returning to the boiler providing acontinuous cycle heating the occupant while the heater is energized.

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the appended claims. My inventionitself, however, both as to its organization and method of operation,together with further objects and advantages thereof, will be bestunderstood by reference to the following description taken inconjunction with the accompanying drawings in which: I

FIG. 1 is a fragmentary side elevational view with portions broken awayillustrating a vehicle seat employing a heat exchange assembly inaccordance with the concept of this invention.

FIG. 2 is an enlarged fragmentary view of a modified portion of the seatback illustrated in FIG. 1.

FIG. 3 is a side elevational view of a vehicle seat with portions brokenaway illustrating another modification of the subject invention.

FIG. 4 is a top plan view of a vehicle seat with portions broken awayillustrating fluid passages therein.

FIG. 5 is an enlarged fragmentary view of a portion of FIG. 4 taken online 55.

FIG. 6 is a side elevational view of a vehicle seat with a portion ofthe seat back broken away to illustrate a further modification of thesubject invention.

FIG. 7 is a top plan view of a seat structure employing passages forheating or cooling both the seat back and the seat bottom in accordancewith the subject invention.

FIG. 8 is a perspective view of the seat assembly shown in FIG. 7 with aportion broken away illustrating provision of an electrical connectionto a heater that is connected to the vehicle electrical system.

With reference to FIG. 1, a vehicle 10 is illustrated including a seatassembly 12 comprising a seat bottom 14 and a seat back 16. The seatback 16 contains foam cushioning material 18 covered by plastic materialsuch as an impermeable vinyl cover 20, the foam cushioning material 18containing a conduit 22 that follows a serpentine upwardly directed paththrough the foam material 18 adjacent the cover 20. The conduit 22 isconnected to a slightly upwardly extending pipe 24 that is connected toa condenser assembly 25 which also has a return pipe 28 connectedthereto. The upper portions 23 of conduit 22 connect with the pipe 24that is connected to the condenser assembly 25 for a purpose laterdescribed. The return pipe 28 connects with a lower boiler portion 30 ofthe serpentine passage 22 completing a closed fluid circuit. Arecharging valve 26 in the return pipe 28 contains a closed pipe fitting32 through which the closed fluid circuit can be filled with a volatilefluid such as trichloromonofluoromethane, commonly referenced as R11Freon. The filling of the closed fluid circuit with the volatile fluidcompletes a heat pipe assembly 34 including the condenser 25 and boiler30 in the closed fluid circuit. The volatile fluid is responsive toslight temperature differentials between the boiler end 30 of the heatpipe assembly 34 and the upper condenser 25 and as long as thetemperature at the boiler 30 is slightly greater than that of condenser25, the assembly functions to vaporize the fluid at the boiler anddischarge heat by condensing the vapors at the condenser providing acontinuous operational cycle. In fact, a temperature differentialextending between the boiler 30 of the heat pipe assembly 34 and thecondenser end 25 of less than 1 F. is sufficient for the volatile fluidto be vaporized at the boiler end 30 causing it to rise as a vaporthrough the upper portion 23 of the serpentine passage 22 and flowthrough passage 24 to the condenser 25 where the vapors discharge heatand condense return flowing as a fluid by gravity through the rechargingvalve 26 and passage 28 to the' boiler 30. The positioning of theserpentine passage 22 adjacent the cover material renders the volatilefluid responsive to body heat supplied at the boiler 30. When the seatis occupied, the volatile fluid is vaporized and rises through theserpentine passage 22 and the pipe 24 to the condenser where itdischarges heat and condenses before flowing by gravity downwardlythrough passage 28 back to the boiler for reheating and revaporizationproviding a continuous cooling effect while the seat is occupied.

With reference to FIG. 2 a modified form of the serpentine passage 22 isillustrated wherein an impermeable formed plastic portion 36 is heat orotherwise sealed to an impermeable plastic face 37 at a plurality ofpoints 38 forming an assembly 39 having a sinuous passage 40 similar tothat provided by the serpentine passage 22 of FIG. 1. The impermeableplastic assembly 39 is positioned between a polyurethane foam cushion 42which is retained by a spring assembly 44 and the adjacent seat cover20. The passage 40 is also filled with a volatile fluid which respondsto heat supplied by the body of an occupant causing the fluid tovaporize and transverse the sinuous passage to the upper portions of theseat back assembly where the vapors flow to the condenser, condense andreturn flow as a liquid through a conduit 45 to the lower boiler end ofthe sinuous passage 40 in the same manner as described with reference toFIG. 1.

A further modification of the subject invention is shown in FIG. 3,wherein a fluid passage 46 is provided adjacent the cover material 20and is likewise filled with a volatile fluid. The volatile fluid isheated at the boiler end 48 and rises through the passage 46 as a vaporand is condensed at the condenser 50 of a heat pipe assembly. The liquidcondensed from the vapors at the condenser 50 flow through a conduit 52through a shut off valve 54 from which the liquid flows through conduit56 to the boiler 48. The shut off valve 54 is operative to discontinuecyclic operation of the heat pipe assembly and is utilized to charge thesystem with the volatile fluid as required. Of course, such a shut offvalve can be provided in any of the embodiments of this invention givingthe seat occupant the option of discontinuing cyclic operation of theheat pipe assembly as he desires.

FIG. 4 illustrates a unit 60 for cooling a seat assembly including alattice network of passages 62 adapted to be placed adjacent the coverof seat 12. The passages 62 connect with a shut off valve 64 through aconduit 66, the shut off valve controlling flow through another conduit68 providing for circulation of a volatile fluid in a closed circuit.The closed circuit of this likewise comprises a heat pipe assemblywherein a slight temperature differential between a boiler input portionof the assembly and an elevated condenser portion of the assemblyresults in a continuous cyclic operation of the fluid. The specificconfiguration of the passages 62, forming the lattice network of FIG. 4,is more specifically shown in FIG. 5 wherein the passages 62 areillustrated as being formed by heat sealing or otherwise securingimpermeable plastic sheets 69 and 70 at a plurality of points 72.

A further modification of the invention is shown in FIG. 6, wherein asealed container 74 is formed between an inner wall of impermeableplastic material 76 and an outer wall of like material, the wallscooperating to define an arcuate chamber 78 in the form of a seat back80. Prior to being tightly sealed, the chamber 78 is filled with both anopen-cell foam 82, such as that obtained from polyurethane, and avolatile fluid forming a heat pipe assembly. As a heat pipe assembly,the sealed container 74 includes a condenser portion 84 and a boilerportion 86 wherein the volatile fluid is heated electrically or inresponse to body heat and cyclically circulates through the open cellfoam as previously described.

FIG. 7 illustrates a further modification of the subject inventionwherein both the seat bottom 14 and the seat back 16 include sinuouspassages 90 and 92, respectively. The passages 90 and 92 connect with acommon boiler cavity 94 which contains a cartridge type electric heater96 capable of dissipating up to 360 watts of electrical energy. Theheater is connected to an electrical power source in the vehicle, notshown, and is controlled through a switch 98 and a thermostat 100. Thepassages 90 and 92 cooperate with the boiler cavity 94 to formrespective heat pipe assemblies 102 and 104,

the respective assemblies including condenser portions 106 and 108 whichare elevated relative to the boiler cavity 94. The heat pipe assemblies102 and 104 contain a volatile fluid, such as the aforementionedtrichloromonofluoromethane thereby providing an assembly operative forboth cooling and warming an occupant of the seat assembly 12. Duringwarm weather conditions the switch 98 is retained in an open positionand the boiler cavity 94 is responsive to the heat supplied by the bodyof an occupant to vaporize the volatile fluid causing it to rise throughthe passages 90 and 92 toward the respective condensers 106 and 108.

The area of contact of the seat occupant with the seat bottom 14 andseat back 16 including portions of the heat pipe assemblies 102 and 104is generally within the area defined by broken line 93. Since the areadefined by line 93 is not subject to being cooled by air flowing withina car body, the temperature within the area will be warmer than ambientair and this heat will vaporize the volatile fluid. The vapor will riseuntil it comes into contact with a cooler surface, such as at thecondenser portions 106 and 108, or even portions of passages 90 and 92as indicated at 95 and 97 respectively which are outside the area ofline 93. Here the volatile fluid will condense and give up its latentheat of condensation, which is dissipated to the ambient air within thecar interior. Regardless of the place of condensation, the condensedfluid will return by gravity to the boiler cavity 94. The result is acooling of the occupant area 93 during warm weather conditions. Theamount of cooling achieved relates to the temperature differentialbetween the area 93 and the ambient air impinging upon condenserportions 106 and 108 or portions 95 and 97, such that the temperaturewithin area 93 approaches within a few degrees the ambient airtemperature.

In an air conditioned car which is usually 70 to 80 F. in cold weatherconditions, switch 98 is closed energizing cartridge heater 96, addingheat to the volatile fluid and vaporizing it for transmission towardcondensers 106 and 108. Since the passages 90 and 92 will be initiallycolder than the heater 96, the vaporized fluid will condense in thepassages 90 and 92, giving up its latent heat of condensation andheating the passages. This process will continue until the condensationeventually takes place in the condenser portions 106 and 108. Thus thevolatile fluid provides a ready means for transporting heat from theheater 96 and distributing it throughout portions 102 and 104 heatingthe occupants body within the area defined by line 93. During theheating cycle, the condensed fluid will return by gravity to the boilercavity 94 for reheating by the cartridge heater 96. By virtue of theenergization of cartridge heater 96, the occupant of the seat iscontinuously warmed as long as switch 98 and thermostat 100 are closed.The thermostat 100 is provided in the circuit so that the occupant canadjust the rate of cycling of the fluid by the heater 96 thereby therebyregulating the amount of heat emitted by the heat pipe assemblies 102and 104. A rheostat type control could be utilized in place ofthermostat 100 to regulate the amount of heat generated by the heater 96by regulating the flow of current therethrough.

A significant feature of this invention resides in the fact that byvirtue of a closed container assembly either provided in a seat pad oras an integral part of a vehicle seat assembly, the heat pipe assemblyprovided thereby is responsive to the heating of the seat as a result ofthe vehicle being parked in a sunlit area and should'the upper portionsof the seat be shaded, the assembly automatically operates to cool theseat prior to being engaged by an occupant. It is apparent from theabove description that a closed container filled with a volatile fluidhaving an elevated portion can readily be provided in any type of seatstructure to accomplish the aforementioned desired results.

While I have shown for purposes of illustration specific forms of theclosed container heat pipe assembly constructed in accordance with thepresent invention in vehicle seat structures, it will be understood thatnumerous variations and alternative constructions may be made withoutdeparting from the true spirit and scope thereof. While the subjectinvention has been shown in specific combination with a vehicle seatstructure, I do not intend to limit my invention thereto except asrequired by the following appended claims.

I claim:

1. A seat structure including a body support having a portion elevatedin relation to other portions, means defining a chamber thereinextending to said elevated portion and said other portions and being inthermal communication with the ambient environment in said elevatedportion and with the body of an occupant in the seat structure in aportion of said other portions, said chamber containing a fluid having aboiling temperature below the temperature of said other portions whenthe seat is occupied and above ambient temperature whereby boilingvapors rise in said chamber to said elevated portion where they condenseinto a liquid and return flow to said other portions for reheating bythe body of the occupant, the heating of said other portions and thecooling at said elevated portion being continuously effective to removeheat added to the fluid as long as a temperature differential existsbetween said other portions and said elevated portion therebycontinuously cooling the occupant.

2. A seat structure including a body support having a portion elevatedin relation to other portions, a heat transfer unit therein extending tosaid elevated portion and said other portions in a sinuous path andbeing in thermal communication with the ambient environment at saidelevated portion and with the body of an occupant in the seat structurein a portion of said other portions, said heat transfer unit containinga fluid having a boiling temperature below the temperature of said otherportions when an occupant of the seat supplies heat thereto and aboveambient temperature, and a selectively energized heater adjacent saidother portions whereby heat supplied by an occupant and heat supplied bysaid heater when energized boils the fluid generating vapors rising tosaid elevated portion where they discharge heat and condense into aliquid return flowing to said other portions for reheating, the boilingof the fluid by heat of the body of an occupant cooling the occupant byvirtue of heat removed at said elevated portion and the boiling of thefluid by heat added by said heater warming the occupant as the fluidtemperature increases above body temperature.

3. A seat structure composed of plastic materials including a bodysupport having a portion elevated in relation to other portions, a heatpipe assembly within said support adjacent body engaged surfaces, saidheat pipe including a sinuous passage formed between sealed plasticmembers of said seat structure, said heat pipe including a condenser inthermal communication with the ambient environment at said elevatedportion and a boiler in thermal communication with an occupant at aportion of said other portions, a return passage in said seat structureconnecting said condenser with said boiler, a selectively energizedelectric heater also in thermal communication with said boiler, saidheat pipe containing a fluid having a boiling temperature below thetemperature of said other portions when an occupant of the seat suppliesheat and above ambient temperature, heat supplied by said heater and anoccupant of said seat boiling the fluid generating vapots rising to saidcondenser where they discharge heat to the ambient environment andcondense into a liquid return flowing to the boiler for reheating, theboiling of the fluid by heat of the body of an occupant cooling theoccupant by virtue of heat being removed at said condenser, theselective boiling of the fluid by said heater warming the occupant asthe fluid temperature increases above body temperature, and a shut offvalve in said return passage operable to discontinue cyclic operation ofthe heat pipe assembly at the option of an occupant.

1. A seat structure including a body support having a portion elevatedin relation to other portions, means defining a chamber thereinextending to said elevated portion and said other portions and being inthermal communication with the ambient environment in said elevatedportion and with the body of an occupant in the seat structure in aportion of said other portions, said chamber containing a fluid having aboiling temperature below the temperature of said other portions whenthe seat is occupied and above ambient temperature whereby boilingvapors rise in said chamber to said elevated portion where they condenseinto a liquid and return flow to said other portions for reheating bythe body of the occupant, the heating of said other portions and thecooling at said elevated portion being continuously effective to removeheat added to the fluid as long as a temperature differential existsbetween said other portions and said elevated portion therebycontinuously cooling the occupant.
 2. A seat structure including a bodysupport having a portion elevated in relation to other portions, a heattransfer unit therein extending to said elevated portion and said otherportions in a sinuous path and being in thermal communication with theambient environment at said elevated portion and with the body of anoccupant in the seat structure in a portion of said other portions, saidheat transfer unit containing a fluid having a boiling temperature belowthe temperature of said other portions when an occupant of the seatsupplies heat thereto and above ambient temperature, and a selectivelyenergized heater adjacent said other portions whereby heat supplied byan occupant and heat supplied by said heater when energized boils thefluid generating vapors rising to said elevated portion where theydischarge heat and condense into a liquid return flowing to said otherportions for reheating, the boiling of the fluid by heat of the body ofan occupant cooling the occupant by virtue of heat removed at saidelevated portion and the boiling of the fluid by heat added by saidheater warming the occupant as the fluid temperature increases abovebody temperature.
 3. A seat structure composed of plastic materialsincluding a body support having a portion elevated in relation to otherportions, a heat pipe assembly within said support adjacent body engagedsurfaces, said heat pipe including a sinuous passage formed betweensealed plastic members of said seat structure, said heat pipe includinga condenser in thermal communication with the ambient environment atsaid elevated portion and a boiler in thermal communication with anoccupant at a portion of said other portions, a return passage in saidseat structure connecting said condenser with said boiler, a selectivelyenergized electric heater also in thermal communication with saidboiler, said heat pipe containing a fluid having a boiling temperaturebelow the temperature of said other portions when an occupant of theseat supplies heat and above ambient temperature, heat supplied by saidheater and an occupant of said seat boiling the fluid generating vaporsrising to said condenser where they discharge heat to the ambientenvironment and condense into a liquid return flowing to the boiler forreheating, the boiling of the fluid by heat of the body of an occupantcooling the occupant by virtue of heat being removed at said condenser,the selective boiling of the fluid by said heater warming the occupantas the fluid temperature increases above body temperature, and a shutoff valve in said return passage operable to discontinue cyclicoperation of the heat pipe assembly at the option of an occupant.